I caught 2 of these in Feerrott: The Dream by the bridge today. No lantern just regular fishing pole and catch-a-lot bait with 96-104 fishing. I got the rare fish message as well.
Head towards Cazic temple while in Feerrott zone. Once you come upon and facing the temple, turn left and run along the wall (east) until you reach the water. Using a fishing pole and small lantern - start fishing. This is a great spot. Caught 12 of these in about 15 minutes or so.